The present invention relates to optical storage devices, and more particularly, to a method and an apparatus for performing blank detection involved with Error Correction Code (ECC) decoding of information read from an optical storage disc.
Digital Versatile Discs (DVDs) and DVD drives are typical of the optical storage discs and optical storage devices, respectively. When the data flow generated by the optical storage device while reading the optical storage disc is interrupted, the decoder for decoding the data flow is not able to output a proper decoded signal. For example, the decoder for decoding the data flow will output a blank signal. A method for solving the data flow interruption problem mentioned above is to perform blank detection on the optical storage disc to control the decoder's decoding action on the data flow according to detection results of the blank detection. In this way, the decoder neither stops outputting signals nor outputs blank signals.
According to the blank detection method of the related art, when a processing unit of a front stage in the optical storage device detects the interruption of the data flow during a reading process, an optical pickup module of the optical storage device will be returned to an earlier location corresponding to data that has already been read but not yet buffered. That is, the optical storage device must reread and buffer the data that has not been buffered for further decoding. As the control of the blank detection mentioned above, the reading action of the optical pickup module, and the buffering control of the data flow correspond to independent control processes respectively, the optical storage device has to firstly perform the reading action of the optical pickup module, secondly perform the blank detection, then perform the reading action of the optical pickup module again, and finally perform the buffering control mentioned above.
As a result of the blank detection method of the related art, although the data flow interruption problem mentioned above is solved, a new problem of repeating the reading action of the optical pickup module is introduced. The optical storage device has to waste time moving the optical pickup module around the same region of the optical storage disc and rereading the same data stored in that region. An improved blank detection method is therefore required so that the performance of the optical storage device may be enhanced.